Flow valves are used in many applications which require the intermittent flow of fluid. Typical flow valves include a flange at one end for joining an adjacent pipe section to form a continuous fluid conduit. The flange provides a bearing surface mating the flow valve with the pipe section. The pipe section is generally joined to the flow valve in a semi-permanent manner, such as by welding or by bolting the pipe section to the flange of the flow valve.
U.S. Pat. No. 5,000,492 to Kemp discloses a bolting ring having a bearing surface for joining a flow valve and an adjacent pipe section to form a continuous fluid conduit. The ring includes a threaded portion and a smooth end portion on the inside diameter of the ring. The smooth end portion is smaller in diameter than the threaded portion and thereby defines a shoulder which serves as a mechanical stop for the flow valve. The cylindrical flow valve is threaded on its outside diameter and the ring is threaded over the valve up to the shoulder to ensure accurate positioning of the ring on the valve. The adjacent pipe section includes an integral bolting flange having longitudinal holes which are aligned with coaxial holes in the bolting ring. The holes receive double-sided threaded bolts and nuts for mechanically joining the flow valve and the pipe section. The bolting ring can be removed and replaced when the bearing surface on the ring is worn, but it cannot be repositioned to distribute wear and thereby extend the life of the bolting ring. Because the bolting flange of the adjacent pipe section is bolted to the bolting ring at a number of locations around the circumference of the ring, the flow valve and the pipe section cannot be quickly and easily disconnected in the field.
For many applications it is necessary that the flow valve and an adjacent pipe section be repeatedly connected and disconnected in the field. When the flow valve and the pipe section must be repeatedly connected and disconnected in the field, it is desirable that the pipe section and the flow valve be quickly and easily coupled and uncoupled. The process of repeatedly connecting and disconnecting the flow valve and the pipe section, however, presents a serious problem because the bearing surface on the flange of the flow valve becomes worn at the locations where the bearing surface mates with the adjacent pipe section. Excessive wear on the bearing surface results in a loose connection which may leak or suddenly disconnect. Therefore, it is important that the flow valve be replaced before a leak or a sudden disconnect has the opportunity to occur. Replacing the flow valve is especially important if use of the flow valve involves high pressure flow or the transfer of volatile liquids.
Flow valves are used to form a temporary continuous conduit for the intermittent transfer of fuel. For example, flow valves are used to join the transfer hose from a fuel storage terminal to the fill pipe of a tanker such that the tanker can be filled from the underneath instead of from the top. One end of the fill pipe is attached to the underside of the tanker while the opposite end is secured to the flow valve. The fluid conduit between the fuel storage terminal and the tanker is completed by mating the flange on the opposite end of the flow valve with a fluid coupling on the free end of the transfer hose from the storage terminal.
The flange is mated with the fluid coupling by a series of circumferentially spaced locking latches on the inside of the coupling which grip a bearing surface provided on the flange. Because the orientation of the flow valve relative to the fluid coupling is fixed, the latches grip the bearing surface at the same locations around the circumference of the flange each time the fluid conduit is formed. The repeated connecting and disconnecting of the flow valve and the fluid coupling causes excessive wear at the circumferential locations around the flange gripped by the latches, and thus necessitates the replacement of the flow valve at regular intervals.
A conventional cast aluminum flow valve for transferring fuel is shown in FIG. 1A. The flow valve 20 has a first end 21 and a second end 23. Flow valve 20 includes a one-piece generally cylindrical, hollow valve housing 22 which comprises an integrally formed annular flange 26 adjacent second end 23. Because flange 26 cannot be repositioned or removed, the entire flow valve 20 must be replaced when bearing surface 28 provided on flange 26 is worn. To prevent the possibility of a leak or sudden disconnect, the flow valve is replaced at regular intervals. Replacement of the entire flow valve, however, is not cost effective when only the bearing surface on the flange is worn because typically the service life of the valve and the valve housing far exceeds the useful life of the flange. Therefore, the useful life of the flange determines, and consequently reduces the service life of the flow valve.
One solution has been to construct the flow valve in two portions temporarily joined by a cylindrical retaining ring. A prior art flow valve of two-piece construction is shown in FIG. 1B. The flow valve 20' has a first end 21' and a second end 23'. Flow valve 21' includes a main valve housing portion 24 and a head valve housing portion 25. Main valve housing portion 24 comprises the valve and a portion of the valve housing structure, while head valve housing portion 25 comprises an annular flange 26' and the remaining valve housing structure. Head portion 25 is removable at retaining ring 27 and can be replaced, but not repositioned, when bearing surface 28' provided on flange 26' is worn. Although the two-piece construction of flow valve 20' improves cost effectiveness by increasing the service life of the flow valve, it introduces another significant problem.
In flow valve 20', the poppet valve seats itself against the seal 29 in head portion 25. Consequently, when head portion 25 and main portion 24 are separated, any fuel remaining in the fill pipe behind flow valve 20' is lost because the poppet valve is no longer seated against seal 29. In addition, removing and replacing head portion 25 of flow valve 20' in the field is time consuming, and if the replacement head portion is not properly connected, a fuel leak or a sudden disconnect can occur.
Accordingly, it is an object of the invention to improve the cost effectiveness of a flow valve by extending the service life of the valve.
It is another object of the invention to provide a flow valve which can be repeatedly mated with a fluid coupling without incurring excessive wear on the flange of the flow valve.
It is another object of the invention to reduce the possibility that a flow valve will leak or suddenly disconnect from a fluid coupling.
It is another object of the invention to provide a flow valve having an annular flange which can be rotationally repositioned to distribute wear on the flange caused by repeated mating with a fluid coupling.
It is another object of the invention to provide a flow valve having an annular flange which can be reversibly repositioned to distribute wear on the flange caused by repeated mating with a fluid coupling.